Asymmetric hydrogenation using the Ru(II)-BINAP or Ru(II)-t-BINAP system (Ruthenium Complexes of 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl or 2,2'-bis(di-p-tolylphosphino)-1,1'-binaphthyl) introduced by Noyori, et al. provides high enantioselectivity over a wide range of substrates with remarkable turnover (Noyori et al. Acc. Chem. Res., 23, 345 (1990)). However, all reports concerning the reduction of .beta.-ketoesters (Noyori et al., J. Am. Chem. Soc. 109, 5856 (1987)) suffer from the need for temperatures greater than 80.degree. C. or hydrogen pressures greater than 6895 N/mm.sup.2 where special apparatus is required (Kitamura et al., Tetrahedron Lett., 32, 4163 (1991); Taber et al, Tetrahedron Lett., 32, 4227 (1991); Keck et al, J. Org. Chem., 56, 6606(1991)).